Structural topology optimization of aircraft wing leading edge fabricated of multilayer composites

Slat is a lift-improvement device at the leading edge of the aircraft construction. This component should be rigid enough under aerodynamic loads, and impact-resistant after a strike from birds or other foreign objects. This work presents a Topology Optimization (TO) strategy in the design of aircraft slat structure, which takes both aerodynamic bearing capacity and multilayer composites into consideration. The proposed structure has two typical characteristics: the topologically optimized cross-section and the layout is functionally gradient. The optimized slat structure is filled with aluminum foam and wrapped by sandwich coatings (laminated by an aluminum honeycomb layer and composite faceplate). Three different layers' arrangements are interpolated and topologically optimized by the approach for comparison. Boundary conditions have considered dynamic shape, de-ice tube and two typical aerodynamic loading cases. The obtained structures are then simulated through the Smooth Particle Hydrodynamics (SPH) bird striking test. Compared to the original metallic slat structure, the TO slat with sandwich shell significantly improves stiffness under aerodynamic load, reduces 28.9% structural weight, absorbs an additional 24.1% of striking energy, and reduces the damaged area by 1.28% in a typical bird striking event on a 2.88 m length slat structure. The proposed layout can be fabricated by matched moulding.